The present invention relates to touch screen devices, and driving devices and driving methods for a touch panel, and in particular, to a touch screen device, and a driving device and driving method for a touch panel having advantages of reducing a driving time.
Display devices such as a liquid crystal display (LCD) and an organic light emitting display (OLED), portable communication devices, and information processing devices perform functions using various input devices. Recently, touch screen devices are being widely used as input devices in electronic devices such as cell phones, smart phones, palm-size personal computers (PCs), and automated teller machines (ATMs).
Touch screen devices perform desired commands by recognizing an input such as a finger, a touch pen, or a stylus on screens of the touch screen devices to write text, draw shapes, or select and execute icons.
Touch screen devices may resistive type or capacitive type touch screen devices depending on the method employed to sense inputs.
A resistive type touch screen device has a configuration where a glass or transparent plastic plate is coated with resistive material and then is covered with a polyester film. The resistive type touch screen device detects resistance variation to sense a touch point when the screen is touched. Resistive type touch screen devices have a drawback of being incapable of sensing a touch when touch pressure is weak.
A capacitive type touch screen device has electrodes on both or one side of a glass or transparent plastic plate and applies a voltage between the electrodes. The capacitive type touch screen device analyzes capacitance variation to sense a touch point when an object such as a finger touches the screen of the capacitive type touch screen device.
The capacitive type touch screen device requires a driving device for measuring capacitance between the electrodes and sensing capacitance variation to sense a touch point. Such a driving device includes a driving circuit for driving respective node capacitors and a sensing circuit for sensing capacitance variations of the respective node capacitors.
Typical driving devices for a touch panel sequentially drive respective node capacitors and then sequentially measure capacitance variations of the node capacitors. Accordingly, conventional driving devices suffer from a problem in that a driving time for sensing a touch point is long. Also, external noise causes touch panels to malfunction.
The above information disclosed in this Background section is provided to enhance understanding of the background of the invention, and therefore it may contain information that may not be prior art.